Hi biskam,
Great question!
You're right to focus on subtle differences in wording between the passage and the answer choice.
Here, the passage states that reports of secondary events have become so commonly reported that the reports are too numerous to all be accurate. The passage then goes on to state that even if asteroids had the maximum possible number of asteroids orbiting them, only about 1 in every 100 occulations would be accompanied by a secondary event. So the passage is talking about the physical limitations on the actual number of secondary events that occur in space.
By contrast, answer choice (D) asks about
reports of secondary occultations. The passage tells us that the maximum possible number of such events is 1 in 100, and also tells us that the reports are far too numerous to all be true. So we can infer that over-reporting is going on, and that the number of reports will exceed 1 in 100 cases.
As to your question about the use of hypothetical language, the passage uses the 1 in 100 figure to demonstrate the hypothetical maximum number of asteroids accompanied by secondary occultations that could physically exist. By contrast, we have a definite number of reports of such sightings. So the shift in language reflects a slight shift in topic: from the maximum number of secondary occultations that could possibly occur to the higher number that are actually being reported.
I hope this helps clear things up. Good luck studying!
Athena Dalton